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Geotria australis 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Cephalaspidomorphi Petromyzontiformes Petromyzontidae

Scientific Name: Geotria australis Gray, 1851
Common Name(s):
English Pouched Lamprey
Spanish Lamprea de Bolsa
Synonym(s):
Geotria allporti G√ľnther, 1872
Macrophthalmia chilensis Plate, 1897
Petromyzon acutidens Philippi, 1865
Petromyzon fonki Philippi, 1865
Velasia chilensis Gray, 1851

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2014
Date Assessed: 2014-07-07
Assessor(s): Closs, G., Franklin, P., David, B., West, D, Crow, S., Allibone, R, Ling, N. & Hitchmough, R.
Reviewer(s): Gibson, C. & Baker, C.
Facilitator/Compiler(s): Gibson, C.
Justification:
The Pouched Lamprey (Geotria australis) is native to southern Australia, New Zealand and south-western South America. It is anadromous, with eggs hatching in freshwater where juveniles reside for up to 4 years before heading out to the open ocean until it grows into a pre-reproductive adult.  Here, they attach onto the gills of other fish and to marine mammals and live as parasites. Individuals return to freshwater to breed, where they spend up to eighteen months maturing sexually before spawning and dying shortly afterwards. Very little is known about the distribution of the marine phase, but it is thought to travel large distances. Generally, freshwater habitats occur at low altitudes. Upon entering freshwater, adults cease feeding and travel upstream. Upstream migrations are stimulated by increases in stream discharge and can occur during the day but are most often found at night. Migrations are linked to the receding flood waters and occur on both small and large flood flows. No specific information is available on the population of this species, although it has undoubtedly declined through recent history. In New Zealand, there is anecdotal evidence of an historic decline and there is no reason to believe this has ceased. Here, this species is nationally assessed as 'Threatened - Nationally Vulnerable', based on expected, on-going population declines as a result of loss of suitable freshwater habitat. The main threats to this species are most likely to be the installation of hydro dams on many major rivers, which has probably affected the abundance and distribution of this species by preventing access to large parts of its former upstream range. Given that spawning is most likely to occur in small, forest streams with cobble and boulder habitat, it is expected that the conversion of most of the lowland forest to farmland in New Zealand has had a profound effect on the distribution and abundance of this species here, as it has on other freshwater fish species. Adults probably now have to travel further upstream to find suitable spawning habitat (which may negatively impact the condition of the adults) and the overall area of suitable spawning habitat has decreased. Due to the lack of data and specific information currently available from across this species' range, particularly on the distribution, population trends and impacts of threats to this species, it has been assessed as Data Deficient.

Geographic Range [top]

Range Description:The Pouched Lamprey (Geotria australis) is native to and widely distributed across the temperate zone of the southern hemisphere, except for South Africa. It occurs in the southwest and southeast corners of Australia, New Zealand, and south western South America in Chile and Argentina (McDowall 2000, James 2008).
Countries occurrence:
Native:
Argentina; Australia (New South Wales, South Australia, Tasmania, Victoria, Western Australia); Chile; Falkland Islands (Malvinas); New Zealand (North Is., South Is.); Uruguay
FAO Marine Fishing Areas:
Native:
Atlantic – southeast; Atlantic – southwest; Indian Ocean – Antarctic; Indian Ocean – eastern; Indian Ocean – western; Pacific – southwest; Pacific – southeast; Pacific – eastern central; Pacific – Antarctic; Pacific – western central
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:No specific information is available on the population of this species, although it has undoubtedly declined through recent history. In New Zealand, there is anecdotal evidence of a historical decline and there is no reason to believe this has ceased. Here, the spawning adult population also undergoes extreme fluctuations, the causes of which are unknown. In New Zealand, this species is nationally assessed as 'Threatened - Nationally Vulnerable', based on expected, on-going population declines as a result of loss of suitable freshwater habitat (Goodman et al. 2014).
Current Population Trend:Unknown
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Geotria australis is anadromous (James 2008). Generally, freshwater habitats occur at low altitudes (NIWA 2013). Eggs hatch in freshwater, where the ammocoetes remain until metamorphosis (thought to be at least 4 years) (NIWA 2013). After about 3-4 years and at a length of about 100 mm, juveniles head out to the open ocean to grow into pre-reproductive adults. Here, they attach onto the gills of other fish and to marine mammals and live as parasites (McDowall 2000, James 2008, NIWA 2013). Very little is known about the distribution of the marine phase, but it is thought to travel large distances. This species returns to freshwater to breed (between April and October in New Zealand and from June-July in south western Australia), where they spend up to 18 months maturing sexually before spawning and dying shortly afterwards (James 2008, NIWA 2013). Upon entering freshwater, adults cease feeding and travel upstream. Upstream migrations mostly occur at night and are associated with the receding flood waters of both small and large flood flows. Upstream migrations of more than 240 km have been recorded (James 2008). Spawning takes place in clear, rocky inland forested streams and adults have the ability to climb. Juveniles reside in soft sediment burrows often in backwaters or stream margins where flow is gentle, near adult spawning habitat. Adults reach a total length of 450-750 mm (McDowall 2000). Generation time is estimated to be nine years.
Systems:Freshwater; Marine
Generation Length (years):9
Movement patterns:Full Migrant

Use and Trade [top]

Use and Trade: Historically, this species was an important food source for Maori in New Zealand and elaborate weirs were constructed to catch them. This traditional fishery still occurs on a small scale in the Whanganui River near Pipiriki (NIWA 2013). Lampreys are harvested during the adult upstream migration phase, not long after they have entered freshwater (James 2008).

Threats [top]

Major Threat(s): The installation of hydro dams on many major rivers has probably affected the abundance and distribution of this species through preventing access to large parts of its former upstream range (James 2008). Given that spawning is most likely to occur in small, boulder forest streams, it is expected that the conversion of most of the lowland forest to farmland in New Zealand has had a profound effect on the distribution and abundance of this species here, as it has on other freshwater fish species. Adults probably now have to travel further upstream to find suitable spawning habitat (which may negatively impact the condition of the adults) and the overall area of suitable spawning habitat has decreased (James 2008). This is confounded by the recently (2011) discovered Lamprey Reddening Syndrome (LRS), which is killing large numbers of pre-reproductive adults during their upstream migration. The cause of this syndrome is yet to be discovered, but LRS may pose a real threat to declining lamprey populations in New Zealand as it occurs across Southland, which is where adult lamprey are thought to be in the highest abundance. It is possible that trout predation on juveniles is also a threat (David pers. obs. 2011). Threats to the adult marine stage are unknown but may include alterations of prey and accumulation of contaminants.

Conservation Actions [top]

Conservation Actions: There are no conservation actions in place for this species. Trap and transfer from below dams to areas upstream may benefit this species.

Citation: Closs, G., Franklin, P., David, B., West, D, Crow, S., Allibone, R, Ling, N. & Hitchmough, R. 2014. Geotria australis. The IUCN Red List of Threatened Species 2014: e.T197275A2480788. . Downloaded on 23 January 2018.
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